In the treatment of patients with lung problems or with the air passages in general, certain respiration techniques are often used to improve their state of health. These concern more specific treatments of patients with acute or chronic obstructive lung disorders, such as coughing, bronchitis, asthma, emphysema, mucoviscidosis etc. . . . , or with acute or chronic restrictive lung disorders such as pneumoconiosis, or also treatments to improve lung and breathing capacity.
Specific inspiration and/or expiration techniques exist for each of these treatments. A first technique, called "positive expiration pressure" (PEP) involves making the patient exhale against increased resistance by making use of a tube with a narrowed opening, as a result of which the air passages are kept open by an increased intrabronchial pressure during expiration. This technique is often used with the aid of an anesthesia mask on which a T-shaped attachment with inspiration and expiration opening is provided on the breathing opening. Through the fact that various attachments with different narrowed openings can be pushed onto the expiration opening, with this appliance the patient can be made to exhale at different expiration pressures, depending on the required treatment. This appliance has various disadvantages: namely that the resistance, and thus the expiration pressure, cannot be adjusted during one and the same expiration. This means that a wrongly selected attachment (too narrow an opening) could cause the patient breathing difficulties. Another factor is that the appliance is difficult to clean, and is relatively expensive in relation to its facilities.
A second, commonly used technique, "intermittent positive expiration pressure", involves making the patient exhale against a varying resistance by interrupting the expiration flow and permitting it again in rapid alternation according to a periodically alternating pattern. This technique is applied by making the patient exhale into a small appliance which has a round ball of light material on the tube opening in the head which widens out vertically like a smoking pipe. Through the expiration this ball carries out upward and downward movements in rapid succession, through the interaction between the expiration pressure (which varies according to the position of the ball) and the force of gravity which, of course, remains constant. The expiration air is thereby interrupted and allowed through intermittently. The object of this technique is to cause vibrations in the air passages, as a result of which excess mucous breaks up, or to increase the overall lung capacity.
The disadvantages of these types of appliances, as they are currently being put on the market, are that they are impractical in use because they cannot be used with the patient lying down (the head must be used vertically), and that they do not permit any variations in the vibration pattern of the ball, or in the expiration resistance, since it is always the same ball which is used, and the expiration opening is not made adjustable. It goes without saying that this fixed expiration resistance cannot be optimum for all patients (e.g. children). Besides, these appliances are very expensive considering their limited facilities.
Another technique which could be applied, and for which no specific appliances are available on the market, involves inspiration against increased resistance, known as "vario orifice inspiration" or "incentive inspiration", the object of which is to bring about a restoration in the balance between the O.sub.2 and the CO.sub.2 tension in the body, which is necessary, for example, in the case of hyperoxygenation syndromes (better known as hyperventilation).